The present invention relates to an improved contact lens conditioning solution. More particularly, it relates to a solution which renders the contact lens surface more wettable so that proteins, lipids and other tear film substituents do not adhere and form deposits on the lens surface.
Contact lenses are typically made of plastic and, therefore, are hydrophobic or water repellant. Since the use of the first contact lenses, there has been a recognized need to use conditioning agents for contact lenses to render the contact lenses more hydrophilic or "wettable". The purpose of these conditioning agents is to render the lens surface more wettable so that proteins, lipids, and other tear film substituents do not adhere and form deposits thereon. Such deposits reduce the comfort and safety of the lens, and also interfere with optical clarity since it is important that the tear fluid spread evenly over the surface of the lens.
Hard contact lenses, such as those fabricated from poly (methylmethacrylate), are of such firmness that contamination can be removed by mechanical means, such as by rubbing a lens soaked in cleaning solution between one's fingers. However, soft contact lenses, such as those fabricated from hydrophilic materials, such as 2-hydroxyethyl methacrylate (HEMA), and some rigid gas permeable (RGP) material lenses, require greater care in removing deposits since cleaning solutions can be absorbed and concentrated in the lens and because the soft lenses are more apt to tear or suffer other damage during mechanical cleaning.
Presently, an enzymatic cleaner consisting of a proteolyic enzyme, such as papain, which is effective in removing protenatious deposits from the contact lens surface, is relied upon to provide a clean lens. The enzyme is typically provided in a kit with vials, into which are placed enzyme tablets. The tablets are dissolved in saline, distilled water or 3% peroxide, and the lenses are typically soaked from between 2 to 6 hours. Following enzymatic cleaning, it is necessary to disinfect the contact lens. A problem exists, however, in that the use of enzymes is expensive and can be quite inconvenient.
Therefore, there exists a need for a conditioning solution which renders a contact lens surface more wettable so that proteins, lipids and other tear film substituents do not adhere thereto and form deposits. There is a further need for such a solution which may be used on hard, RGP and hydrogel (soft) contact lenses. Such a conditioning solution would greatly enhance the cleaning operations now required.